Magnetic memory cell including two-terminal selector device

• US 10,593,727 B2
• Filed: 01/05/2018
• Issued: 03/17/2020
• Est. Priority Date: 05/18/2016
• Status: Active Grant

• Current Assignee: Avalanche Technology Incorporated
• Original Assignee: Avalanche Technology Incorporated
• Inventors: Yang, Hongxin, Yen, Bing K., Zhang, Jing
• Primary Examiner(s): Nguyen, Duy T
• Application Number:
  US15/863,825
• Publication Number:
  US 20180240845A1
• Time in Patent Office: 802 Days
• Field of Search: 257421
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: G11C 11/1659 Cell access
• CPC Class Codes: G11C 11/1673 Reading or sensing circuits or methods
• CPC Class Codes: G11C 11/1675 Writing or programming circuits or methods
• CPC Class Codes: G11C 16/10 Programming or data input circuits
• CPC Class Codes: H10B 61/10 comprising components having two electrodes, e.g. diodes or MIM elements
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 50/85 Magnetic active materials
• CPC Class Codes: H10N 70/245 the species being metal cations, e.g. programmable metallization cells

Abstract

The present invention is directed to a memory cell that includes a magnetic tunnel junction (MTJ) memory element and a two-terminal selector element coupled in series. The MTJ memory element includes a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween. The magnetic reference layer structure includes one or more magnetic reference layers having a first invariable magnetization direction substantially perpendicular to layer planes thereof. The two-terminal selector element includes a first inert electrode and a second inert electrode with a volatile switching layer interposed therebetween; a first active electrode formed adjacent to the first inert electrode; and a second active electrode formed adjacent to the second inert electrode. The volatile switching layer includes a plurality of metal-rich particles or clusters embedded in a matrix or at least one conductor layer interleaved with insulating layers.

Claims

1. A memory cell comprising:

a magnetic tunnel junction (MTJ) memory element including a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween, said magnetic free layer structure including one or more magnetic free layers having a variable magnetization direction substantially perpendicular to layer planes thereof, said magnetic reference layer structure including one or more magnetic reference layers having a first invariable magnetization direction substantially perpendicular to layer planes thereof; and

a two-terminal selector element coupled to said MTJ memory element in series, said two-terminal selector element including;

a first electrode and a second electrode with a volatile switching layer interposed therebetween, said volatile switching layer including a plurality of metal-rich particles or clusters embedded in an insulating matrix;

a third electrode formed adjacent to said first electrode opposite said volatile switching layer; and

a fourth electrode formed adjacent to said second electrode opposite said volatile switching layer.

2. The memory cell of claim 1, wherein said insulating matrix is made of an oxide.

3. The memory cell of claim 1, wherein said insulating matrix comprises hafnium and oxygen.

4. The memory cell of claim 1, wherein said first and second electrodes are inert electrodes.

5. The memory cell of claim 1, wherein said first and second electrodes are made of titanium nitride.

6. The memory cell of claim 1, wherein said first and second electrodes are made of a same conductive material selected from the group consisting of tantalum nitride, titanium silicide, nickel silicide, cobalt silicide, and any combinations thereof.

7. The memory cell of claim 1, wherein said third and fourth electrodes are active electrodes.

8. The memory cell of claim 1, wherein said first and second electrodes are inert electrodes, and said third and fourth electrodes are active electrodes.

9. The memory cell of claim 1, wherein said plurality of metal-rich particles or clusters and said third and fourth electrodes are made of a same material.

10. The memory cell of claim 1, wherein said plurality of metal-rich particles or clusters and said third and fourth electrodes are made of silver.

11. The memory cell of claim 1, wherein said plurality of metal-rich particles or clusters and said third and fourth electrodes are made of a same material selected from the group consisting of copper, cobalt, nickel, and any combinations thereof.

12. The memory cell of claim 1, wherein said two-terminal selector element further includes a fifth electrode formed adjacent to said third electrode opposite said first electrode and a sixth electrode formed adjacent to said fourth electrode opposite said second electrode.

13. The memory cell of claim 12, wherein said fifth and sixth electrodes are inert electrodes.

14. The memory cell of claim 12, wherein said fifth electrode is made of iridium, ruthenium, or platinum, said sixth electrode is made of iridium, ruthenium, or platinum.

15. The memory cell of claim 1, wherein said MTJ memory element further includes a magnetic fixed layer structure exchanged coupled to said magnetic reference layer structure through an anti-ferromagnetic coupling layer, said magnetic fixed layer structure having a second invariable magnetization direction that is substantially perpendicular to a layer plane thereof and is opposite to said first invariable magnetization direction.